She arrives slightly late for this interview at Hamilton Gardens, spots staff member Sue Harris coming out of her office, and Nathan quickly launches into a "grovelly" request about seating at the upcoming Waikato Times Hamilton Gardens Arts Festival.

It's something to do with the chairs being left in place after the Malvina Major concert, so they'll be all set up for the following night's Sunset Symphony, and thus save a lot of extra lugging about.

Nathan is the festival director, Harris is the Gardens customer service manager, and there is a bit of banter on both sides as they negotiate the matter. Although Nathan doesn't get a definite yes, she seems a hard person to say no to.

She hopes for a good outcome as she walks away, just one more small detail (actually, quite big when you're talking several hundred heavy metal chairs) to deal with in the intricate web of the festival.

She's recently had a heart-stopping moment over the Shakespeare production, a festival favourite staged annually by Slip of the Tongue theatre group. Nathan got a call from group member Alec Forbes to say that, for various reasons, they just couldn't deliver this year's rendition of Twelfth Night. With the programme already printed, Nathan knew it would be impossible to contact the hundreds of people who usually turn up for Shakespeare.

"I thought, We will do it. There's no way you can't have a Shakespeare."

Within six hours, other city theatre groups had offered to step into the gap. There was an emergency meeting at 11 that night at Iguana restaurant in town, the result being that actors from Slip of the Tongue, Full House, Apocalypse Lounge and Crossmatch Theatre have united to stage A Midsummer Night's Dream at the festival.

Whew, Nathan says, as she describes the co-operative spirit.

"A worst nightmare has turned into a clear image of the health of theatre in Hamilton and how much people care about this festival."

Nathan herself cares deeply about the festival. This is her third year as director, but she has 10 years as a festival performer under her belt, and this has wedded her to the city's primo summer event.

"I fell in love with it as an actor. I was always in the pantomime, did Shakespeare and other things. It's a magical combination of creativity and the outdoor setting, a chemical reaction that comes from these two things, and just creates joy."

The pleasure has been percolating at Hamilton Gardens since 1998, and Nathan and her team are now gearing up for the 13th festival, to be held February 17 to March 1.

A highlight of the inaugural festival was the Turtle Lake concert, where Hamilton-born opera star Dame Malvina Major performed with Taiwanese singer Tommy Lee, the Auckland Philharmonic and other artists. Dame Malvina is a headliner again this year, part of an ambitious programme of about 200 individual performances.

Gardens director Peter Sergel recalls the first festival being organised with a budget of around $9000, and a lot of goodwill from various people and organisations.

It was designed as a hallmark event, part of a Gardens' marketing plan. About 27,000 people attended, and it rolled on for another year. And another, and a city summer tradition was firmly established. Albeit with a few hiccups over the years caused mainly by wet weather, and funding and sponsorship worries.

Originally run by Gardens' staff with support from Friends of Hamilton Gardens, it subsequently came under the umbrella of a trust, and directors were employed as the festival's popularity and diversity increased.

Sergel has a wad of programmes from the past which chart the growth. The lineup for the second event of 1999 looks slim pickings by today's standards, but the stalwarts are all there in the form of Shakespeare, jazz, opera, art, kids' picnic, wine and food.

Some of the planning was done on the wing. Sergel remembers "grabbing an Estonian choir" to perform at an early festival, just because they happened to be touring at the time.

He says there are about 30 different arts festivals held around the country, but the Gardens setting makes Hamilton's unique, with shows matched to perfect performance spaces.

He mentions a couple of examples from this year's programme, the Italian play Venturina Venturina, to be held in the intimate Italian Medici Court, and a dance performance at the Chinese Scholars Garden.

The Shakespeare production will be at the new Tudor Garden - designed by Sergel - with eight figures of mythical beasts set around an intricate knot garden.

The project is still under development, but the mythical beasts will be in place for the shows, and the audience will sit in the space that will later be planted as the knot garden.

Another perfect match of performance and location, one more thing to add to festival history.

Sarah Nathan is specially mindful of the history, and of safeguarding the event for the future. As various other festivals and high profile concerts have struggled recently in a difficult financial climate, she says the Hamilton strategy will be about sustainability, and thinking smarter rather than bigger, considering what's affordable, and what's not.

"The [trust] board and I have such a responsibility to care for this event."

Nathan adds that the festival cannot just engage high-priced events because of a perceived demand for them, and financial risks lie in the top-end events. Sustainability may mean trimming back the programme in the future, and perhaps relishing "small scale events in unique spaces".

The not-for-profit festival currently has a cash budget of about $500,000, and perhaps another $200,000 extra in contra deals. Nathan says this is "chicken feed" compared with the multi-million dollar budget for the upcoming New Zealand Festival of the Arts in Wellington.

But Hamilton has to cut its cloth according to its income, and it is heavily reliant on its sponsors and funders to run the programme.

Nathan says they operate on a financial model similar to the famous Edinburgh Festival. The Hamilton outfit provides the venue, marketing and technical support for all scheduled artists and events, and artists take a substantial share of their box office sales.

While this means the risk is primarily with the artists, Nathan says there is a sense of responsibility on her part that "they walk away with their pants intact".

This year's programme covers theatre, dance, music, film, comedy, an art award, readers and writers, wine and food, and more. There is big stuff and small stuff, using many corners of the garden. A number of events are free, and others around $15 to $20. Dame Malvina Major and Glenn Shorrock - "Voice of the Little River Band" - are the top-priced acts at $45 and $40 respectively. Again, these are modest prices compared with some festivals.

Nathan says ticket sales are going well - even though Hamiltonians have a tendency to book late - and some shows are almost sold out. But she won't relax until they reach their targets. Dame Malvina and Shorrock will perform on the big stage at the Rhododendron Lawn, which could cope with 5000 people.

"I'll be very happy with 1000."

Last year between 80,000-100,000 people attended the festival; the numbers were slightly down on expectations and possibly affected by the Christchurch earthquake which happened in the middle of it, causing upset nationwide. In 2010 when the size of the programme was increased, ticket sales grew by 250 per cent.

Festival trust chairman Chris Williams is pleased with the way things are shaping up, with a "fantastic" programme on offer.

Like Nathan, this is his third season, and he got involved because he thinks it's a great event for the city, he saw its potential, that it could grow in stature, and he wanted to help Nathan bring it to another level. The festival earned a top accolade last year when it gained the "outstanding event" award at the New Zealand Recreation Association's annual ceremony.

Williams is the chief executive of Hamilton's King St Advertising, and he says his work for the festival is also a way to put something back into the local creative community.

He absolutely backs Nathan's ability. "She is one of those people who is like hen's teeth. She has artistic appreciation and ability combined with management and organisational skills. She is unbelievable in what she is able to pull together. Very few people could do it. It will continue to grow in stature."

Williams plans to attend something every day of the festival, and as an "old rocker" he has Glenn Shorrock firmly in his sights. He's also looking forward to the special screening of Rocky Horror Picture Show, as well as some theatre, including Venturina Venturina in the Medici Court, and the Hollywood satireFour Dogs and a Bonein the American Modernist Garden.

Four Dogs and a Bone is a collaboration between city theatre group Full House, and Auckland-based professional actor Stuart Devenie. Devenie is a well-known face on Kiwi stages, and he's a strong supporter of the Hamilton festival. He worked with Full House last year on The Miser of Mystery Creek, and performed his solo show Hatch in 2010.

Devenie loves the variety of performance spaces the Gardens offers, and says this year's venue of the American Modernist Garden is a perfect fit with Four Dogs and a Bone.

He's seen Hamilton audiences growing in both numbers and appreciation, and has seen presentation standards lift as well.

"Twenty-five years ago you couldn't bring a play to Hamilton," he says. "Last year when we did The Miser of Mystery Creek you could see the pride and enjoyment in the audience. This was their story."

Devenie likes his association with Full House - "they have a strong focus on development, and raising their skills", and nowadays he knows his way around the city. "It's a pleasure to work in Hamilton."

Nathan's on the last lap with planning, down to details about chairs and such. She's not alone at this time of the year.

Her husband Hamish comes on board over three months as logistics manager, working on staffing, marquees, infrastructure, traffic management, light, sound, rubbish and more.

"Process and detail are his absolute strengths," she says.

Hamish, Sarah adds, will be celebrating his 40th birthday during the festival and will be on site on the big day, rather than partying at home. "The poor bugger, he doesn't have any choice," says his wife.

Nathan will put in long hours during the festival, "overseeing everything, going to every event". She greets artists, makes sure they're briefed, talks to sponsors, is everywhere.

She praises the strong support from Gardens staff, and many others who help. The festival draws in extra workers from the Waikato Dragon Boat Association, making a donation in recompense, and also employs several students and others over the two weeks. Everyone gets lunch and dinner in another stalwart operation run by Gardens' customer services staffers Sue Harris and Pamela Hide.

Nathan sees the pleasure on the faces of the festival-goers - "smiles on smiles" - and it fuels her, keeps her going through mad moments of anxiety and crisis.

This year Nathan mused about adding to her commitments by maybe taking a very small role in the Shakespeare production. She rolls her eyes; Hamish apparently responded "no way, no way," when she floated the possibility at home.